Getting unix timestamp from Date()

Question

I can convert a unix timestamp to a Date() object by putting the long value into the Date() constructor. For eg: I could have it as new Date(1318762128031).

But after that, how can I get back the unix timestamp from the Date() object?

you can still get the long value of your Date object, can't u? — Kent
– Kent, Commented Oct 16, 2011 at 13:03
@xEnOn: you're not converting a Unix timestamp into a date by using the long constructor. A Unix timestamp, as I commented on jackrabbit's answer, is expressed in seconds, not milliseconds. Here: en.wikipedia.org/wiki/Unix_time and here: unixtimestamp.com/index.php Seconds. Not milliseconds. — TacticalCoder
– TacticalCoder, Commented Oct 16, 2011 at 15:06

jackrabbit · Accepted Answer · 2019-12-07 08:25:42Z

105

getTime() retrieves the milliseconds since Jan 1, 1970 GMT passed to the constructor. It should not be too hard to get the Unix time (same, but in seconds) from that.

edited Dec 7, 2019 at 8:25

answered Oct 16, 2011 at 13:02

jackrabbit

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4 Comments

Carven Over a year ago

Thanks. I kept remembering it wrongly as a static function Date.getTime(new Date()) which didn't work and thought what was going on.

TacticalCoder Over a year ago

@jackrabbit: actually getTime() doesn't give back the Unix timestamp but "Unix timestamp * 1000". The agreed defintion about the Unix timestamp is that it gives times since the epoch in second, not milliseconds ; )

dognose Over a year ago

@TacticalCoder jackrabbit is more accurate: It returns the unix-timestamp in milliseconds. Yes, the unix-timestamp is agreed to be in seconds - but if your answer would be true, (getTime() = unixTimestamp * 1000), getTime() would always return three Zeros at the end, but in fact can return anything from ending with 000 to 999, which means it has a higher precision due to milliseconds and is not just "*1000". Meaning: Comparing a real unixTimestamp*1000 with the getTime() result would only succeed in ~0.1% of the cases.

Onat Korucu Over a year ago

For the record, the function returns the miliseconds in GMT-0 area (in Greenwich), So you can be safe about converting this to different areas.

Pedro Lobito · Accepted Answer · 2019-06-08 10:17:36Z

56

To get a timestamp from Date(), you'll need to divide getTime() by 1000, i.e. :

Date currentDate = new Date();
currentDate.getTime() / 1000;
// 1397132691

or simply:

long unixTime = System.currentTimeMillis() / 1000L;

edited Jun 8, 2019 at 10:17

answered Apr 10, 2014 at 12:30

Pedro Lobito

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1 Comment

MarkHu Over a year ago

Or more tersely: new Date().getTime()

Kedar Tendolkar · Accepted Answer · 2017-11-09 18:10:05Z

26

import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.TimeZone;

public class Timeconversion {
    private DateFormat dateFormat = new SimpleDateFormat("yyyyMMddHHmm", Locale.ENGLISH); //Specify your locale

    public long timeConversion(String time) {
        long unixTime = 0;
        dateFormat.setTimeZone(TimeZone.getTimeZone("GMT+5:30")); //Specify your timezone
        try {
            unixTime = dateFormat.parse(time).getTime();
            unixTime = unixTime / 1000;
        } catch (ParseException e) {
            e.printStackTrace();
        }
        return unixTime;
    }
}

edited Nov 9, 2017 at 18:10

Kedar Tendolkar

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answered Nov 3, 2012 at 4:59

bhasker

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Comments

waterscar · Accepted Answer · 2017-01-24 09:21:12Z

8

In java 8, it's convenient to use the new date lib and getEpochSecond method to get the timestamp (it's in second)

Instant.now().getEpochSecond();

answered Jan 24, 2017 at 9:21

waterscar

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2 Comments

Milan Velebit Over a year ago

But the code presented returns the # of seconds for this moment

Anonymous Over a year ago

True, @MilanVelebit. You will have to substitute your desired Instant instead of Instant.now(). Or yourDesiredJavaUtilDate.toInstant() if you got an old-fashioned Date from a legacy API.

Arvind Kumar Avinash · Accepted Answer · 2025-08-30 09:57:59Z

tl;dr

java.time.Instant
.ofEpochMilli( 1_318_762_128_031L )  // From count to moment.
.toEpochMilli()                      // From moment to count.

1318762128031

Modern Java

In Java 8+, use the java.time classes.

Never use the terribly flawed legacy classes, such as Date, Calendar, SimpleDateFormat, Timestamp, etc.

From count to moment

You apparently have a count of milliseconds since the epoch reference of the first moment of 1970 in UTC, 1970-01-01T00:00Z.

I could have it as new Date(1318762128031)

Instant instant = Instant.ofEpochMilli( 1_318_762_128_031L ) ;

Generate text in standard ISO 8601 format.

String output = instant.toString() ;

Run this code at Ideone.com.

2011-10-16T10:48:48.031Z

From moment to count

You said:

how can I get back the unix timestamp from the Date() object?

Interrogate the Instant object.

long count = instant.toEpochMilli() ;

We get the same long number as where we started.

1318762128031

elverde · Accepted Answer · 2014-06-18 11:51:17Z

0

I dont know if you want to achieve that in js or java, in js the simplest way to get the unix timestampt (this is time in seconds from 1/1/1970) it's as follows:

var myDate = new Date();
console.log(+myDate); // +myDateObject give you the unix from that date

answered Jun 18, 2014 at 11:51

elverde

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Comments

AlexR · Accepted Answer · 2011-10-16 13:10:18Z

-2

Use SimpleDateFormat class. Take a look on its javadoc: it explains how to use format switches.

answered Oct 16, 2011 at 13:10

AlexR

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